1. Field of the Invention
The present invention relates generally to memory devices and, more particularly, to a technique and apparatus for accelerating a burn-in cycle in memory devices.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art which may be related to various aspects of the present invention which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Microprocessor-controlled integrated circuits are used in a wide variety of applications. Such applications include personal computers, vehicle control systems, telephone networks, and a host of consumer products. As is well known, microprocessors are essentially generic devices that perform specific functions under the control of a software program. This program is stored in a memory device which is coupled to the microprocessor. Not only does the microprocessor access memory devices to retrieve the program instructions, but it also stores and retrieves data created during execution of the program in one or more memory devices.
There are a variety of different memory devices available for use in microprocessor-based systems. The type of memory device chosen for a specific function within a microprocessor-based system generally depends upon which features of the memory are best suited to perform the particular function. Memory manufacturers provide an array of innovative fast memory chips for various applications, including Dynamic Random Access Memories (DRAM), which are lower in cost but have slower data rates, and Static Random Access Memories (SRAM), which are more costly but offer higher data rates.
Memory devices are typically mass produced by fabricating thousands of identical circuit patterns on a single semiconductor wafer and subsequently dividing them into identical die or chips. To produce the integrated circuit, many commonly known processes are used to modify, remove, and deposit material onto the semiconductor wafer, which is generally made of silicon. Once the active and passive parts are fabricated in and on the wafer surface, one or more layers of conductive material, such as metal, for electrically connecting circuit components is added, and a protective layer is deposited over the silicon wafer. The wafer is visually evaluated and electrically tested to determine which memory devices are good so that they may be packaged for use.
During the testing, the memory devices are generally “burned-in” to ensure that the cells, which are located at particular rows and columns within the memory device, are able to store data for future access reliably. Generally, burn-in includes writing data to each memory cell and then reading the data from the memory cell. The data read from each memory cell may then be compared to the data which was written to the memory cell to verify that the cell is storing the data properly. DRAMs are generally burned-in such that more than one row for a particular column can be burned-in simultaneously. However, SRAMs are generally burned-in one cell at a time since the write drivers in SRAMs are generally not able to drive enough current to write to several cells simultaneously, because the load is too great to be driven by the write driver. It would be advantageous to provide a technique for simultaneously burning in more than one row for a particular column in an SRAM device.
The present invention may address one or more of the problems set forth above.